Field of the Invention
The present invention relates to an optical apparatus.
Description of the Related Art
Japanese Patent Laid-Open No. (“JP”) 2009-3122 discloses an image pickup apparatus that provides phase difference detecting pixels in part of an image sensor and realizes autofocus (“AF”) of a phase difference detecting method (so-called “image-pickup-plane phase-difference AF”) utilizing them. JP 2010-282085 discloses an image pickup apparatus that uses two focus detecting methods, such as the image-pickup-plane phase-difference AF and a contrast AF (referred to as a “TV-AF” hereinafter). JP 2010-139942 proposes a method for calculating the focus detecting precision of the image-pickup-plane phase-difference AF.
In general, the in-focus precision of the phase difference AF is lower than that of the TV-AF, and the method of JP 2009-3122 is likely to have a lower in-focus precision. According to the method of JP 2010-282085, as a wobbling amount of the focus lens increases, for example, when an F-number is large, an image magnification variation of the live view capturing or an image taken in the motion image capturing can be remarkable and the image quality deteriorates. For example, when an interchangeable lens configured to provide the TV-AF is attached to a camera body configured to provide the image-pickup-plane phase-difference AF, a selection of one of the AF methods becomes an issue.